This invention relates to tracheal tube assemblies and liners for such assemblies.
Tracheal tubes are used to provide a gas passage to a patient's trachea. The patient end of the tube is inserted in the trachea and may be sealed with it by means of an inflatable cuff encircling the tube close to the patient end. The machine end of the tube extends out through the patient's mouth, in the case of an endotracheal tube, or through a surgically-made stoma in the patient's throat, in the case of a tracheostomy tube.
In use, secretions within the trachea and bronchii tend to build up on the bore through the tracheal tube, especially where the tube remains in place for a prolonged time, such as several days. This leads to problems in that the secretions can obstruct gas passage through the tube causing difficulties in breathing or ventilation. The secretions can also provide a site for the accumulation of bacteria which, if dislodged, can be inhaled by the patient and cause bronchial infection.
To reduce the adverse effects of this, it has been proposed to use a liner or inner tube which is inserted within the tracheal tube and which is removed and replaced by a fresh liner periodically. Tracheal tube assemblies including such liners have been described, for example in WO 91/12844 and WO 91/12845. The liner usually has a fitment at its machine end which is located with the machine end coupling on the tracheal tube and may be held in place by the mating coupling on ventilation tubing coupled to the tracheal tube. These connectors may be of the straight-through kind in which the ventilation tube is coupled coaxially of the machine end of the tracheal tube. Alternatively, the connector may be right-angled so that the ventilation tubing is led away at right angles to the machine end of the tracheal tube. The right-angle connector has advantages in that ventilation tubing can lie close to the patient, leading to a reduction in the force exerted on the tracheostomy or mouth by the weight of the tubing. Also, the right-angle connector can have an axial port enabling the introduction of a suction catheter, as required, into the bronchii.
Where the right-angle connector, the tracheal tube and its liner are made by the same manufacturer, to conform with one another, provision is made to retain the liner in its correct position. However, it is often the case that the connector will be made by a different manufacturer and that the liner will, therefore, not be held firmly in the tracheal tube by the connector. This leads to the risk that the liner may move rearwardly along the tracheal tube, such as on a sudden exhalation, and project into the connector, causing the right-angle port to be blocked either completely or to such an extent that breathing is severely impaired.